1. Field of the Invention
The invention relates generally to the replacement of piping which passes through earth fills and particularly relates to a method and apparatus for removing and replacing pipe which is imbedded in an earth fill or the like without excavation of the fill.
2. Description of the Prior Art
Rural water service systems have come to use small diameter piping formed of various relatively rigid plastics and metal such as copper, this piping being typically from 3/4" diameter to sizes ranging to 2" in diameter and greater. The great majority of the conduit piping or tubing used in such systems for transporting water have diameters of approximately 3/4" to 1". This piping or tubing is subject to wear as is any conduit used to transport liquids, it being necessary to replace the piping on a periodic basis. This piping is also subject to damage from a variety of environmental factors, particularly freezing, and is sometimes damaged due to accident. In such situations, it is often necessary to replace at least portions of the piping including pipe portions which pass through earth fills such as roadways and the like. In such circumstances, it has been necessary to excavate the earth fill in order to remove the worn or damaged piping and to replace this piping with new piping, the excavation process being time consuming and laborious whether accomplished manually or with excavation equipment. Even under the best of circumstances, labor and equipment costs cause pipe replacement according to the prior art to be an expensive undertaking. Rural water service systems, in particular, must tolerate substantial expenses due to the need to replace worn or damaged piping.
While the prior art has previously provided methods and apparatus directed to the replacement of old service mains with new pipe structure, the prior art has not provided fully satisfactory methodology and apparatus directed to the particular problems encountered in removing and replacing piping beneath earth fills such as is described above. In U.S. Pat. No. 1,897,561 to Manucci et al, a device is disclosed for replacing an old service main with a new pipe. Pedone, in U.S. Pat. No. 4,006,521, describes a device for removing old pipe and replacing the old pipe with new pipe. Williams, in U.S. Pat. No. 4,309,128 and Parish, in U.S. Pat. No. 4,422,800, describe devices for removing pipe embedded within the earth. The structures disclosed in the foregoing patents, while useful in certain situations in which the use of the devices were intended, do not provide apparatus capable of rapidly and economically removing and replacing flexible piping of the nature of that used in situations such as are encountered in rural water service systems wherein small diameter plastic or metal piping is embedded within earth fills such as under roadways. The devices of the prior art are not directed to structure capable of being rapidly adapted to piping of differing diameters. Further, the devices of the prior art do not provide the ability to lubricate an earth channel from which old pipe is being pulled and new pipe simultaneously placed into the position originally occupied by the old pipe. The present methodology and structure intend solution to the problems encountered in the prior art and provide the ability to rapidly and economically replace and repair old or damaged plastic or metal conduit pipe with a minimum expenditure of time and labor.